Sailing catamaran with pivoting hulls



3 Sheets-Sheet 1 HULL ,9. B. MITCHELL SAILING CATAMARAN WITH PIVOTINGHULLS May 5, 1970 Filed May 20, 1968 TH/Q/S BE/Q//V C/QT/V/Q/V- /D (//A/INVENTOR May 5, 1970 c. B. MITCHELL 3,509,842

SAILING CATAMARAN WITH PIvoTING HuLLs Filed May 20, 1968 3 Sheets-Sheet2 /MHJZ P/ V07 RHA/6E F7 THN/Q/Q/QAf/VD i//L/ INVENTOR.

May 5, 1970 c. B. MITCHELL 3,509,842

SAILING CATAMARAN WITH PIVOTING HULLS Filed May 20. 1968 3 Sheets-Sheet3 56H57/ LOCK [PM/N50 No Toms Rf@ UAV/Q50) B-R//V LOCK l O 55cm/N5PRH/v5 HC/L @0770/7 INVENTOR.

United States Patent O 3,509,842 SAILING CATAMARAN WITH PIVOTING HULLSCharles B. Mitchell, Loudonville, N.Y. (RD. 4, Ballston Spa, N.Y. 12020)Filed May 20, 1968, Ser. No. 731,366

Int. Cl. B231) 1/18 U.S. Cl. 114-61 2 Claims This invention is designedto overcome a common fault of all conventional sailing hulls, includingthe catamaran. This fault is that the conventional hull changes theangle of contact between hull surface and Surface of water upon beingheeled over by wind. When this occurs there is a loss of efciency by thehull directly related to the angle of tilt. Severe heeling can result inlugging with little increase in speed and possible capsizing due to thechanging for-ces acting upon the hulls varying surface.

The catamaran of this invention utilizes twin atbottomed hulls that areconnected to a frame by parallel, bearing-held tubes such that the hullscan freely pivot over a range of A (see FIG. 2) degrees from center. Thecenter line of the pivot bearing and tube is offset inward by distance X(see FIG. 2) from the hull center line. The pivot bearings are attachedto the bottom of the hull to place it below the buoyancy line.

With the above described design the catamaran will always maintain theleeward hull in the same respective position to the water line. This istrue even if the wind causes sufficient heeling to lift the Windwardhull clear of the water due to the tilt of the mast and frame.

Therefore, the advantages to be gained are numerous. As the Wind forcesbuild, both horizontal and vertical forces against the leeward hullincrease as it maintains its same position relative to the water line.This gives increased resistance to side drift and increased lift,respec- "lee tively. From this, additional speed is gained since waterfriction is reduced.

FIG. l and FIG. 2 illustra-te how the hulls are attached to the frame bythe pivot bearings and the relative position of the pivot center linewith respect to the hull center line. Angle in FIG. 2 is the angle thatwould be maintained by the leeward hull as the frame is pivoted in thewind through angle 7x.

FIG. 3 illustrates the construction of the pivot bearing assembly. Itssimplicity and the ease with which the tube may be inserted and removedshould be noted. Simply by throwing back the safety lock, swinging upthe bearing lock and then the hold down bearing bar the way is clear forthe tube to be lifted out. This is a highly desirable featureto providequick dismantling and/or assembly and ease of transportability.

Having thus described the invention, what I claim as new and desire tobe secured by Letters Patent is as follows:

1. A sailing catamaran where each hull of said catamaran is hinged atthe bottom of the supporting arms: the pivots being offset inwardly fromeach hulls centerline so as Ito cause the outside of each hull to ridehigher than the inside at a predetermined angle, whereby regardless ofthe heeling of the catamaran due to wind force, the hull alwaysmaintains the same angle to the water level.

2. A sailing catamaran where each hull of said catamaran is pivoted, thepivots being offset inwardly from each hulls centerline so that thehulls ride at a predetermined angle to the water level so that whenrunning into or across the wind the lee hull is always planing intothewind and fighting against drifting to leeward.

References Cited UNITED STATES PATENTS 3,116,708 1/ 1964 Gardhouse114-61 ANDREW H. FARRELL, Primary Examiner U.S. C1. X.R. 114-39

